Construction of silsesquioxane and phosphinum-based ionic porous hypercrosslinked polymers for efficient heterogeneous catalytic CO2 cycloaddition

In this work, we reported a facile one-pot route to construct polyhedral oligomeric silsesquioxane (POSS) and phosphonium-based ionic porous hypercrosslinked polymers (denoted as P-iPHCPs) with multiple catalytic active sites, which could be regarded as efficient heterogeneous catalysts for the conversion of carbon dioxide (CO2) to highly value-added cyclic carbonates. The targeted polymers P-iPHCPs were prepared from a rigid building block octavinylsilsesquioxane (VPOSS) and a low-cost commercially available organic ionic salt methyltriphenylphosphonium bromide ([Ph3PMe]Br) by the AlCl3-catalyzed Friedel-Crafts reaction. The series of polymers P-iPHCPs that synthesized by different molar ratios of VPOSS to [Ph3PMe]Br possess hierarchical micro/mesoporous structures with high surface areas ranging from 376 to 429 m(2) g(-1) and behave the flower-like nano-morphology. Especially, the desired multiple active sites involved the mixed anions including free Cl-, Br- anions and the in-situ formed metal-halogen complex anion [AlCl3Br](-) within phosphonium segments, and the enriched POSS-derived Si-OH hydrogen bond donor (HBD) groups that derived from the breakage of POSS cages during the synthetic process. The typical polymer P-iPHCP-14 has the aforementioned nucleophilic-electrophilic multiple catalytic active sites, which was regarded as an efficient recyclable heterogeneous catalyst for synergistic catalytic conversion of CO2 with various epoxides into cyclic carbonates under mild conditions.

Automated summary

A facile method was reported to construct polyhedral oligomeric silsesquioxane (POSS) and phosphonium-based ionic porous hypercrosslinked polymers (P-iPHCPs) with multiple catalytic active sites. These polymers, with hierarchical micro/mesoporous structures and flower-like nano-morphology, serve as efficient heterogeneous catalysts for the conversion of carbon dioxide (CO2) to valuable cyclic carbonates. Particularly, polymer P-iPHCP-14 exhibits high efficiency in the synergistic catalytic conversion of CO2 with various epoxides to cyclic carbonates under mild conditions, and is recyclable.